Starpharma Secures FDA Validation for DEP HER2 Radiotherapy Trial Design
FDA greenlights Starpharma’s clinical pathway for DEP HER2 radiotherapy candidate
Starpharma (ASX: SPL) has received positive FDA feedback on its proposed first-in-human phase 1 clinical study design for DEP HER2. The regulatory alignment, secured through a Type C guidance meeting with the US FDA, validates the company’s clinical development strategy for its HER2 receptor-targeting dendrimer conjugate with a lutetium-177 radionuclide payload.
DEP HER2 is being developed for locally advanced or metastatic HER2-overexpressing gastric/gastro-oesophageal junction cancers and other HER2 expressing advanced cancers in patients who have received prior HER2-targeted therapy. The initial European FIH study will enrol up to 15 patients, with clinic entry remaining on track for H2 CY 2026.
The FDA alignment de-risks the regulatory pathway and provides critical validation for Starpharma’s clinical development strategy in the high-growth radioligand therapy market.
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What is targeted radioligand therapy and why does it matter?
Targeted radioligand therapy represents a precision approach to cancer treatment where radioactive payloads are delivered directly to cancer cells via molecules that recognise specific markers on tumour surfaces.
Lutetium-177 radionuclide payloads work by emitting targeted radiation that damages cancer cell DNA when bound to tumour cells expressing specific receptors. This localised radiation delivery aims to maximise tumour destruction whilst minimising damage to surrounding healthy tissue.
Starpharma’s dendrimer technology platform provides the delivery scaffold for DEP HER2. Dendrimers are precise, synthetically manufactured, nanoscale molecules with unique properties—including their size, structure, high degree of branching, polyvalency, and water solubility—that make them advantageous for pharmaceutical applications.
HER2 overexpression is a key driver in aggressive breast and gastric cancers. Patients who have exhausted HER2-directed therapies represent a population with significant unmet medical need, as limited treatment options remain available after progression, resistance, or toxicity from current therapies.
The radioligand therapy market is experiencing rapid growth, and Starpharma’s dendrimer platform differentiates its approach by enabling targeted delivery benefits specific to radiotherapeutics.
DEP HER2’s three key components:
- HER2-targeting moiety — binds to HER2 receptors overexpressed on cancer cells
- Dendrimer platform — provides the delivery scaffold with precise nanoscale structure
- Lutetium-177 payload — emits targeted radiation to damage tumour cell DNA
Key regulatory confirmations from the FDA
The FDA meeting delivered three critical regulatory confirmations that strengthen Starpharma’s development pathway and reduce execution risk.
Clinical data pathway
The FDA confirmed clinical data generated outside the US (in Europe), combined with the preclinical data package including a recently completed formal toxicology study, should be adequate to support future US-based clinical studies under an Investigational New Drug (IND) application.
This provides a clear pathway to US market entry without requiring US-based FIH studies, enabling Starpharma to progress European clinical development whilst retaining the option for subsequent US regulatory submission.
Manufacturing validation
The FDA provided clear guidance on chemistry, manufacturing and controls (CMC) expectations for DEP HER2. The regulator agreed with Starpharma’s current approach to the manufacture and characterisation of its novel dendrimer-based radioligand therapy.
CMC alignment reduces development risk and supports regulatory submission timelines by confirming manufacturing processes meet regulatory standards before costly clinical escalation.
Accelerated pathway potential
The FDA confirmed that patients with advanced HER2-expressing cancers who have exhausted available HER2-directed therapies represent a population with significant unmet medical need. This confirmation means Starpharma has potential to pursue Fast Track designation and other accelerated development pathways for DEP HER2 in the future.
Accelerated pathways can significantly reduce time to market by enabling earlier approval based on surrogate endpoints, provided clinical benefit is demonstrated.
Professor Tony Lahoutte, MD, PhD
Head of the Department of Nuclear Medicine at University Hospital (UZ) Brussel“The FDA’s feedback provides important confirmation that Starpharma’s first-in-human phase 1 design and overall clinical strategy for DEP HER2 are in line with regulatory expectations. From a nuclear medicine and radiopharmaceutical perspective, the proposed approach to patient selection, dosimetry and safety evaluation is appropriate.”
Clinical study design and next steps
The planned FIH phase 1 study will be conducted in Europe initially in up to 15 patients. Study objectives include evaluating safety and tolerability, characterising pharmacokinetics, biodistribution and organ radiation dosimetry of DEP HER2 in patients with advanced HER2-positive cancers.
Clinical site selection is complete, and Starpharma is progressing radiopharmacy preparations, site onboarding and required ethics and regulatory approvals. The study remains on track to begin in H2 CY 2026.
| Study Parameter | Detail |
|---|---|
| Location | Europe initially |
| Patient Population | Up to 15 patients with advanced HER2-positive cancers |
| Objectives | Safety, tolerability, pharmacokinetics, biodistribution, organ radiation dosimetry |
| Timeline | H2 CY 2026 |
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Strategic positioning for Starpharma’s dendrimer platform
DEP HER2 represents a key strategic asset within Starpharma’s broader portfolio. The company has two decades of experience advancing dendrimer technology from lab to patient, with a portfolio that includes three clinical-stage DEP assets, preclinical radiopharmaceutical assets, research collaborations, and three commercially marketed OTC products.
Starpharma aims to broaden therapeutic applications and commercial opportunities of its dendrimer platform in the high-growth radiotherapy sector. By demonstrating the value of DEP technology in a clinical setting, the company seeks to exemplify the platform’s potential whilst delivering meaningful outcomes for patients with significant unmet needs.
Cheryl Maley
Chief Executive Officer, Starpharma“DEP HER2 is a key strategic asset for Starpharma, supported by comprehensive preclinical data and a clinically validated platform technology. We are particularly excited by the encouraging data generated to date, which have shown important benefits in targeted delivery for radiotherapeutics.”
Maley highlighted the significance of the FDA feedback: “This is an important milestone, providing regulatory clarity and validation for the proposed clinical development pathway and marking the exciting transition from preclinical to clinical development. The guidance provides confidence that our current preclinical package, together with the data generated in the forthcoming first-in-patient study, would support a subsequent IND application and clinical development in the US.”
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